The present disclosure relates generally to electrostatographic reproduction machines, and more particularly, concerns a dual purpose surface-treating blade assembly for removing random spots from, as well as cleaning edge areas of, a moving image bearing surface within such a machine.
In a typical toner image reproduction machine, for example an electrostatographic printing process machine, an imaging region of a toner image bearing member such as a photoconductive member is charged to a substantially uniform potential so as to sensitize the surface thereof. The charged portion of the photoconductive member is irradiated or exposed to a light image of an original document being reproduced. Exposure of the charged photoconductive member selectively dissipates the charges thereon in the irradiated areas. This records an electrostatic latent image on the photoconductive member corresponding to the informational areas contained within the original document.
After the electrostatic latent image is recorded on the photoconductive member, the latent image is developed by bringing a developer material into contact therewith. Generally, the developer material comprises toner particles adhering triboelectrically to carrier granules. The toner particles are attracted from the carrier granules to the latent image forming a toner powder image on the photoconductive member. The toner powder image is then transferred from the photoconductive member to a copy sheet. The toner particles are heated to permanently affix the powder image to the copy sheet. Residual toner particles remaining on the photoconductive surface following image transfer as above are then removed by a cleaning apparatus and the surface treated in order to prepare the surface for forming another toner image.
The foregoing generally describes a typical black and white electrostatographic printing machine. With the advent of multicolor electrophotography, it is desirable to use an image-on-image architecture that comprises a plurality of image forming stations. One example of the plural image forming station architecture utilizes an image-on-image (IOI) system in that the photoreceptive member is recharged, re-imaged and developed for each color separation. This charging, imaging, developing and recharging, re-imaging and developing, all followed by transfer to paper, is done in a single revolution of the photoreceptor in so-called single pass machines, while multi-pass architectures form each color separation with a single charge, image and develop, with separate transfer operations for each color. Again as above, residual toner particles remaining on the photoconductive surface following image transfer as above are then removed by a cleaning apparatus and the surface treated in order to prepare the surface for forming another toner image.
It has been found that image-on-image processes, for example, create very high toner densities on the photoconductive or photoreceptor surface. In some machines using toner particles with toner additives in similar multi-color processes, the additional use of control patches, and engagements in component-disturbing activities such as recovery from paper jams, together create conditions that make cleaning or removal of residual toner particles from the imaging region as well as elsewhere very challenging for ordinary conventional cleaning apparatus. The situation is made worse when such conditions are combined with higher process speeds, and demands for higher print quality, longer component lives and higher machine reliability.
The following references disclose examples of existing surface cleaning and treating devices. U.S. Pat. No. 5,214,479 issued May 25, 1993 and entitled “BTR air cleaner with biased shims” discloses apparatus for cleaning residual toner and paper fiber residue from a biased transfer roll (BTR) in an electrophotographic apparatus using high velocity air and substantially contactless flexible biased conductive shims. The high velocity air flow between the BTR and two thin conductive flex-shims is created by means of a blower that evacuates the air in the cleaner housing vacuum chamber. The high velocity air, in combination with the electrically biased BTR and flex-shims, removes residue from the BTR surface and carries it into the vacuum chamber and deposits the residue in a filter bag. The BTR biased shim cleaner system is low cost, efficient and significantly smaller than current BTR cleaning devices.
U.S. Pat. No. 5,732,320 issued Mar. 24, 1998 and entitled “Cleaning blade” discloses a spots cleaning blade for use in a cleaning apparatus in an imaging apparatus for cleaning agglomerate particles from an imaging surface, the spots cleaning blade comprising a polyether urethane and having a high hardness and low coefficient of friction.
U.S. Pat. No. 5,724,640 issued Mar. 3, 1998 and entitled “Floating backer and mount for cleaning blades and spots blades on belt imaging surfaces” discloses apparatus for cleaning particles from a surface using a floating backer and cleaning or spots blade mounted to allow freedom to follow the location of the imaging surface. The cleaning or spots blade controls tolerances when the blade and the floating backer are mounted to a frame pivoted from a fixed photoreceptor backer. This freedom allows a minimization of the tolerances in blade load against the surface or photoreceptor, the blade angle to the photoreceptor and in the location of the blade relative to the backer. This floating backer and blade mount also minimizes the wrap required on the photoreceptor backers adjacent to the blade.
U.S. Pat. No. 6,282,401 issued Aug. 28, 2001 and entitled “Hard cleaning blade for cleaning an imaging member” discloses a relatively hard cleaning blade for use in a cleaning apparatus in an imaging apparatus for cleaning residual toner particles, including dry and liquid ink toners and carriers, from an imaging surface, the cleaning blade having a material having a hardness of from about 86 to about 120 Shore A.
As disclosed in the above examples, the uses of existing cleaning devices such as cleaning brushes and cleaning blades along with other existing surface treating devices such as spots blades, are well known. For a number of reasons including surface cleaning or treatment requirements that are often dictated by the nature of the adhesive forces holding residual toner particles to the photoreceptor surface, such existing cleaning devices and existing surface treatment devices in the above examples are typically adapted for cleaning and treating the imaging region of the photoreceptor image bearing surfaces. Accordingly, they are unsuitable and not adapted for effectively cleaning and treating the edge or margin regions that flank the imaging region of the photoreceptor image bearing surface.
It has been found that desired image quality can be detrimentally affected by a build up of airborne or spilled over toner particles and dirt on the edge or margin regions of the photoreceptor, that is, the regions that are outside of, and flank the imaging region of the photoreceptor surface. The build up occurs because the existing cleaning devices (such as a brush cleaner) and treatment devices (such as a conventional spots blade) are adapted to, and function to clean and treat only the imaging region.
Therefore, in electrostatographic toner image reproduction machines, there is still a need for a toner image bearing surface cleaning and treating apparatus that is adapted to both clean and treat the imaging regions as well as the edge or margin regions of the toner image bearing or photoreceptor surface.